Use of Virtual Dipole Shear Source in Offshore Shear Wave Exploration Without Any Contact to the Seafloor

The acquisition of shear waves is known as indispensable to investigate lithological properties of subsurface materials. Since it is difficult to generate shear waves in the marine environment due to lack of rigidity in the sea water, lithological properties of subsurface materials have been mainly acquired using well logs and AVO in the offshore. Recently, a shear source installed on the seabed has been developed, although the practical deployment and installation of it to the seabed have several difficulties due to the environmental impact and the survey efficiency. In this study, we propose to apply the seismic interferometric technique based on the concept of the virtual dipole source in water to realize the practical marine shear wave exploration. We first introduce the concept of the virtual dipole source and interferometric technique we apply. We then conduct numerical experiments for validating the effectiveness of our method. After that we discuss the possibility of the offshore shear wave exploration without any contacting the seismic source to the seafloor.